Nibbler attachment for power machines



. B. F. scHMlDT 2,387,411

NIBBLER ATTACHMENT FOR POWERY MACHINES oct. 23, 1 945.

Filed Dec. 19, 1944 3 Sheets-Sheet l Oct. 23, 1945. B. F. SCHMIDT y2,387,411

` NIBBLER ATTACHMENT FOR POWER MACHINES y Filed Dec. 19, 1944 .'5Sheets-,Sheet 2 2g @Ai/1 f4 MGM/Aw 12ga, 1f 49 4 A 12b 12A 42 Gttorneg 5Sheets-Sheet 3 Oct 23@ 1945. 4a. F. SCHMIDT Y NIBBLER ATTACHMENT FORPOWER MACHINES Filed bec. 19, 1944 Patented Oct. 23, 1945 My invention'relates to sheen metal fainting machinery `and hasparticular referenceto a cutting machineA of the type known as a"nibbler, particularlyadapted to be employed as an attachment for drill presses or other powertools in which power is supplied to a rotatingshaft.

Metal cutting machines of the type known as nibblers, in which a cutteror die isrecprocated relative to a die plate for the purpose of cuttinga series of small bits of metal from apiece of sheet metal to produce aline of cut `ol anyvdei sired shape, arein relatively common use infactories fabricating articles from sheet metal.

These machines, however, require considerable floor space in the shopwhich might more readily be occupied by othermetal fabricating machinesand, in addition, require a considerable investi ment due to the factthatthese machines are in most instances constructed as a complete unitparatus for actuating the `reciprocating cutters.

`It is therefore an object of my invention to i provide a metal cuttingmachine of the nibbler 125 wherein the attachment may be formed as arelatively small unit attacliablefto' the drill press for other powerdrivenmachine through the medium of the ordinary chuck employed upon theo machine with which it is to be associated.

i It is another object ofmy invention to provide a device of thecharacter set forth `wherein the nibbler attachment may be constructedas a unit within a suitable housing and in which the power `forreciprocating the cutter is supplied through a shaft projecting from thehousing `to be received in and engaged by the chuck of a drill `pressor. similar driven machine.

' Another object of my invention is to provide a nibbler attachment ofthe characterdescribed i which may be readily attached to ordisconnected from existing power machines in a shop by providing anoperating shaft for the nibbler attachment to beengaged by the chuck ofthe drill press or other power` driven machine in the shop and byproviding an arm which may be readily connected to some-stationary partof the drill press or other power machine to holdthe housing of .30`Another object ofmy invention is to provide a nibbling machine `of' thecharacter described 4, f 2387411 f NinnEnn'rTACHMENT FOR POWER l I lMACHINES QSchmidt, Los Angeles, Calif.

ilibeprie, 1944, serial Notariaat?, n

the nibbler attachment gagainstv rotation'as'the shaft ofthenibblereattachmentis rotated.- 1

Other objects 'and advantages of my invention will be apparent from avstudvof` the following specifications; read in connection with theaccompanying drawings, wherein-z` f i Fig. 1 is an elevational -viewrof4a portionof a drill press and illustrating the-manner in which mynibbler attachmentl may be Aassociated there- Fig. 2 is a horizontalsectional View taken along the line II-II of Fig. 1; o o

Fig. 3 is an enlarged vertical sectional view of the nibbler attachmentshown in Fig.- 1 and illustrating the position` of? the parts when `thecutter is retracted from the die; Y Fig. `4 is a View similar toFig.A 3but illustrating theposition of the parts when thecutter is initsprojected position relative `to its die;V

Fig, 5Nis an enlarged frontelevational View of vthe nibbler attachmentshown in Fig. 1, the lower portion ofcertain of the parts being brokenaway to illustrate in section the assembly of the cutter anddie, thesection being taken along the lineV-Vwf Fig. 3; Y .i

Fig. `(iis a bottom plan view of the nibbler `attachment shown in Figs.1 through 5;l

Fig. l"I is a horizontal sectional View, taken alone` the` lineVII-VIIof Fig. 3; K

Fig. `8 is a vertical sectional view taken Lalong theline VIII-VIII ofFig. 3; y V

ffFigyQis a horizontal sectional View taken along the line IX-IX of Fig.3;

Fig.v 10 is a vertical sectional View taken throughl a modified form ofnilblolerv attachment which may be employed in the practice of myinvention and illustrating the position of ther parts when the cutter isin its projected position relative to the die; V

Fig. 11 is a view similar to Figf l0 and illustrating the position ofthe parts when the cutter is in its retracted position relative to thedie Fig. 12 is a front elevational view of the form of nibblerattachment illustrated in Figs. 10 and 11;

Fig. 13 is a vertical sectional view taken along the line XIII--XIII ofFig. 10; i

Fig. 14 is a bottom plan view of the nibbler attachment shown in Figs.10 through 13; and

Fig. 15 is a horizontal `sectional view taken along the line XV-XV ofFig. 10.

Referring to the drawings, I have illustrated in Fig. 1 a conventionaltype of drill press which comprises a vertically extending upright postI, the lower end of which is secured to a suitable base (not shown)while upon the upper end of press usually also comprises awork-supporting table I adapted to be adjusted vertically relative tothe spindle 2 along the upright post I.

In Fig. 1 I` have illustrated my nibbler attachment as being indicatedgenerally by the reference character II comprising a suitable housing I2from which extends a shaft I3 to 'be received and gripped by the drillchuck 4, the housing I2 having secured thereto a horizontally extendingarm or bar I4 adapted to extend past the upright post I of the drillpress to engage the same where it may be heldin place by means of anysuitable fastening, such as a length of flexible material I5 adapted tobe detachably secured to the bar I4 as indicated at I 6. The arm I4illustrated in Figs. 1 and 2 preferably extends along the left-hand sideof the upright po-st I When the drill press is viewed from the front soto engage against the post to resist the right-hand turning movementimparted to the shaft I3.

For convenience in manufacture, I have illustrated the housing as beingformed of two separate elements I2a and I2b, the element I2a having a,longitudinal bore I1 extending from its upper end, being enlarged asindicated at vI9 for the reception therein of a combination of thrustand roller` bearing I 9 in which the rotatable shaft I3 is mounted,while the lowerend of the bore I 'I is of reduced diameter as indicatedat 2U for the purpose of receiving a reduced diameter por- ;:ion oftheshaft I3 and acts as a bearing there- Intermediate the thrust bearingI9 and the bearing bore portion 20, a cam 2l is formed upon the shaft I3for the purpose of producing a horizontal reciprocatory motion upon athrust arm 22 as the shaft I 3 is rotated.

The thrust arm 22 is illustrated as a substantially rectangular block ofmetal extending `through and bearing upon a rectangular opening 23 inthe forward wall of the housing section IZa, the left-hand end of theblock 22 being bifurcated as indicated at 24 (Fig. 7) for the purposekof receiving the upper end of a crank arm 25 therein, the block 22having a transverse bore through which extends a pin 26 by which theblock 22 and the crank arm 25 are interconnected, the crank arm 25 beingprovided with a longitudinally elongated opening` 21 adapting the -pin26 to move upwardly and downwardly with respect to the block 22 as theblock 22 is reciprocated in the horizontal direction. The block 22 isnormally urged toward the left, as indicated in Figs. 3 and 7, as bymeans of a relatively strong-biasing spring 28`which bears against theend of the block 22 at one end and against a cap screw 29 at itsopposite end, which isin turn threaded'into the forward or outer wall ofthe housing section I2b.

The crank arm 25 is illustrated as being pivotecl as at 30 upon thehousing section I2a and having a forwardly extending portion 3| adapted.to rest upon a thrust block 32 Which Prefclbly comprises the cutter ofthe nibbler. As illustrated in Figs. 3 vand 4, the thrust block 22 hasits lower end cut away to leavea relatively narrow cutting blade 33which, as the block 22 is reciprocated horizontally, will move up anddown relative to a die 34 which is secured to the housing section I2b asby means of a screw or cross pin 35 extending transversely through thehousing section I2b. Also it will be observed that the cutter block 32is preferably cut away as indicated at 36 while the die block is alsocut away as indicated at 31 to provide a space accommodating a spring 39which normally urges the cutter 33 upwardly relative to the die block34.

The die block 34 is preferably L-shaped, as viewed in Figs. 3 and 4, andhas a vertical bore 49 of approximately the same shape and the same sizeas the cutter 33 formed therethrough so that when the crank arm 25 isurged toward the left as viewed in Figs. 3 and 4, the cutter 33 willpenetrate into the bore 49. 1

Referring particularly to Figs.'3`, 4, 5 and 8, the lower leg of the Lformed by the die block 34 is spaced downwardly from the housing sectionI2b by a distance sufcient to permit the admission therebetween of asheet of metal or other material to be nibbled or cut by the nibblerwhile, as viewed in Fig. 5, the width of the vertical leg of the dieblock 34 is substantially equal to the width of the cutter 33 so thatupon each stroke of the cutter 33 the section of metal which will beremoved from the sheet of metal to be nibbled or cut thereby will havea. width substantially equal to the width of the neck or verticalsection of the L-shaped die block, thus permittingv the sheet of metalto be advanced to such position as to place an uncut section of thesheet-of metal against the front face of the neck of the die block 34.

With the construction thus far described itgwill be apparent thatrotation of the shaft I3 will, by rotating the cam 2 I, cause the crankarm25 to be oscillated about its pivot 39 and to cause the cutter 33 tobe moved rst downwardly to make a cut and then upwardly to allow thesheet of metal to'be advanced against the neck of the die block 34. Thecut or chip which has been'taken out of the sheet of metal passes downthrough the bore 4D.

Upon the lower end of the housing 'I2 I prefer to provide a guide 4I forthe purpose of limiting the thickness of metal of the sheet which can beemployed with my nibbler attachment, the guide 4|- being constructed :asa substantially U-shaped block of metal secured as by means yof a screw42 to the lower'end of the housing .section I2a, the forward portion ofVthe lU-shaped guide block being held in alignment withthe cutter and dieblock by means of a finger 43Y adjustably mounted as by means of a screw44upon the front 4face of the housing section I2b. The finger 43 has itslower end formed to substantially lit between the legs of the U and'thushold the U from any transverse movement relative to the die block andcutter. By making the finger 43 adjustable vertically relative tothehousing section I2b. it will be apparent that movement of the iinger 43downwardly relative to the housing I2b will constitute a further limitto the distance between the die block 34 and the cutter V33, thusfurther limiting the thickness of metal which maybe cut by the nibblerattachment herein described.

This adjustment is readily made byproviding an elongated slotted opening45 in the finger 43 v ting operation.

downwardly the space `may be limited to substantially the thickness ofthe particular piene `of` metal to be cutiandf permit substantially novertical movement of the metal to be cut as the nibbler operates toperform its nibbling or cut- As ie wen known inthe ext of nibbiers, the

l cutter 43, after it has made a cut and is retracted from the piece ofmetal to be cut, tends to drag the sheet of metal withit so that it isnecessary for `the operator to provide a substantial down- `wardpressure during the upward movement of the cutter. By` properlyadjusting the finger 43 to the proper width to conform with the sheet ofmetal to be cut, the necessity of such downward pressure is avoided andthe sheet of metal may" be more readily guided by the operator into thecutter withall of the attention of the operator concentrated upondirecting the sheet of metal toward the cutter along the desired line ofcut.

While the cam 2| may have any desired configuration, I have illustratedin Fig. 7 a preferred cross section of the cam as being substantiallycylindrical but having a cut away portion at its center having a lengthlongitudinally of the` shaft `33 approximately the height of theblock22. The cam portion is formed as the cut the drill press, asillustrated in Fig. 1, the table I thereof will be lowered slightlybelow the lowwhich are cut away from the piece of sheet metal.

As illustrated particularly in Figs. 2, land 9, the cutter 33 and thedieblock 34 are formed as a unitwhich may be of substantially circular lcross section and inserted bodily into a, circular bore 48`formed in thelower end of the housing member I2, thus facilitating the ready removalof the cutter and die block and the insertion in place thereof of othercutters and die blocks where it is desired to make a wider or a narrowerY cut in the ,sheet metal to be cut by the nibbler.

` Also it will be observed from an inspection of Figs. 1, 2 and 3 thatthe housing portions |2a and I2b may be readily assembled together as bymeans of elongated screws 49 and 50facilitating the cutting orforming ofthe `necessary openings therein for the reception of the shaft I3 andthe crank arm 25. The bar I4 may be secured to the nibbler housingin anysuitable fashion though I prefer that the same be secured as by means*of a plurality of screws 5I extending through `the bar I4 into thehousing section I2b while the housing I2a may have a bracket 52 securedthereto as by means of screw 53 which is in turn riveted or otherwisesecured as indicated at 54 to the bar I4.

One advantage of the construction illustrated in Figs. 1 through 9 isthat the cutter 33 is relatively narrow in its front to back dimension,thus permitting a relatively narrow strip to be cut ermost portion ofthe die block 34 so as to insure u f'ample room for the escape of chipsor cuttings from the side edge ofV a piece of sheet metalfor othermaterial to beV cut thereby as by feeding the samer sidewise (front toback as viewed in Figs. 1 through 4). For example, the cutter 33 mayhave a dimension of approximately fag of an inch so. that if it isdesired to trim a. Very narrow stripfromthe side edge of a piece ofmaterial all that is necessary is to feed the same sidewise `between thecutter 33 and the die block 34 and the total extent `of the cut whichwill be made will not exceed the front `to back dimension of the cutter33.

Also it will be observed that the finger 43, by virtue of its up anddown adjustment, will act as a. presser foot engaging the upper surfaceof the sheet of material to be cut, avoiding the necessity ofutilization of any additional mechanism when very thin metal is to becut by the inibbler.

Referring particularly to Figs- 10 through 15, I have illustrated anibbler attachment of the character set forth but with the modificationthat the cut is made on the up stroke of the cutter rather than upon thedown stroke thereof, as in Figs. 1 through 9.

In this form of the device the shaft I3a is mounted in `a suitable boreformed in the housing 6I which, like the housing I2, is preferablyformed as two separate portions Gla and 62a. for convenience inmanufacture. The shaft I3a. i's received within the bore 60 whichpreferably mounts a combination thrust and roller bearing 63 preferablyseated in an enlargement of the bore E0 at the upper end of the housingsection 6I and held in place therein by the bar I4a which issubstantially in all respects identical with the bar I4 as describedwith reference to Figs. 1 through 9. The bar I4a extends across the 'topof the assem-bled housing sections Bla and 62a and has a downwardlydepending lip 64 extending downwardly in front of the housing section 6Ia. The bar I4a may be secured to the housing 6I in any suitable manneras by means of a plurality of screws 65 which, in View of the fact thatit is necessary in the construction. of the housing section 62 to millout a substantially large opening 66 for the reception therein of acrank arm 61, are threaded intobores 68 as indicated in Fig. 3, thesebores being but slightly larger in diameter than the width of the milledcut 66 formed in the housing section 62a so as to provide the necessaryengagement for the threads of the screw 65.

The bar Illa, like bar I4, extends from the nibbler attachment housing6I rearwardly and is engaged with the upright post of the drill press inthe same manner as was described with reference to Figs. 1 through 9.

However, in this form of the device the cam 69 on the shaft I3a and thepush block 22a are arranged in such manner as to provide for anoscillatory motion of the crank arm 61 substantially opposite to thatprovided for thecrank arm 25 illustrated in Figs. 1 through 9. The crankarm 61 is pivoted as indicated at 10 in the hous- T 'ing section 62a,its longer leg being provided with an elongated opening 1I, throughwhich a pin 12 passes to interconnect the push bar 22a with the crankarm. A suitable spring 13 is bifurcated as indicated at 14 for thereception of the long arm of the crank arm 51. The short arm 15 of thecrank arm 61 has a nose-piece 16 which engages a notch 11 formed in acutter l18 so that as the crank arm 61 is oscillated about its pivot 10the cutter 18 will be first drawn upwardly and then downwardly `within averti- `callyV extending slot 19 section 6 I a.

In this form of the device I prefer to make the die' block l80 as apiece of metal independent of and as'an attachment to the housing memberE Ia. The die block 80 has an opening 8| extending therethrough, throughwhich the cutter 18 reciprocates. -By forming the die block 88 with averticallyextending slot 82 adjacent its forward surface and byproviding an adjusting screw 83 extending horizontally through the frontface of the die block 88, it will be apparent that the die block 88 maybe adjusted to take up for any wear which may occur as a result of .therepeated cutting operations of the cutter 18; that is, if the die blockwears to the extent that it fails to present a sharp edge to the forwardface oflthe cutter 18, tightening the screw 83 will slightly bend thedie block 80, thus drawing the cutting edge 84- close into juxtapositionto the forward face of the cutter 18.

The die block 80 is preferably secured to the front face of the housingsection Bla as by means of screws 85, 86 and 81, the heads of the screws88 being preferably counter-sunk into the front face'of the die block 80past the slot 82 so that they will not interfere with the adjustment tobe performedrby the screw 83. Also to aid in the proper positioning ofthe die block 80 on the housing section Bla, I prefer to provide a pairof locating pins 88 formed upon the housing section Bla to be insertedin suitably aligned openings in the front face of the adjustable dieblock 80.

Located upon the lower face of the die block 80 is a relatively thinstrip of metal 89 adapted to be held in place thereon by means of ascrew 98, the plate 89 being preferably formed with a narrow opening,the width of which is sufficiently wide to accommodate the left to rightdimensions of the cutter 18 while the forward edge of the plate 89 ispreferably beveled as indicated at 9| to engage in a suitably bevelededge formed in the adjustable front face of the die block 88. Thus byforming the strip 89 of relatively hard steel a replaceable die block isreadily formed which, as the die block wears as a result of the cuttingoperations, may be moved slightly rearwardly by the adjustment of thescrew 83 to bring a substantially fresh surface adjacent the forwardsurface of the cutter 18, rendering the strip 89 substantiallyself-sharpening by reason of its contact with the cutter 18 during thecutting operations. For the purpose of permitting this adjustment theopening through which the screw y90 extends is preferably elongated in afront to back relation so that while the head of the screw 90 will holdthe same in position it will permit the front to back adjustment as thescrew 83 is turned inwardly.

While I have illustrated the nibbler attachformed in the` housing Ymentsof my invention as being associated with a standard drill press, it willbe apparent that they may be readily adapted for attachment to electricpower drills or any other machine which has a rotatable spindle to whichthe shaft i3d may be coupled for rotation so that all that is necessaryis to couple the shaft I3 or I3a to the rotatable spindle and to securethe bar I4 or Ida in position relative to some stationary part of thepower machine so as to resist the effect of the rotation of the shaft I3or I 3a.

It will be apparent that once the nibbler attachment has been put inplace, it may be used as a means for forming cuts of various shapes inpieces of sheet metal fed toward the cutters 33 or 18 or fed sidewiserelative to these cutters as hereinbefore describedr-fWhat is equallyimportant is Y that when it is not desired to employ the nibbler it maybe readily .removed from the power machine to which it has been attachedand stored in some suitable location, permitting the use of the powermachine for other purposes Without the necessity of employing floorspace which would otherwise be required for a complete nibbler machine.I

It will therefore be apparent that I have provided a nibbler attachmentwhich will perform all of the services of a nibbling machine but whichmay be used only when it is desired to make cuts in sheet material.

While I have shown and described the preferred embodiment of myinvention, I do not desire to be limited to any of the details ofconstruction shown and described herein, except as defined in theappended claims. f v

I claim:

1. In a nibbler attachment for attachment to a power machine having arotatable spindle, a housing, a rotatable shaft supported in saidhousing for attachment to the spindle of the power machine and having acam formed thereon, a bellcrank pivoted in said housing, a push barrecipro cably mounted in said housing for engagement with said cam,means attaching said push bar with one arm of said bellcrank, a nibblercomprising a die block and a` cutter reciprocahly mounted relative tosaid die block, one end of said cutter bearing against one arm of saidbellcrank for reciprocation thereby as said shaft is rotated, and springmeans for urging said push bar against said cam.

2, In a nibbler attachment for attachmentvto a power machine having arotatable spindle; a housing, a rotatable shaft supported in saidhousing for attachment to the spindle of the power machine and having acam formed thereon, a bellcrank pivoted in said housing,'a push barreciprocably mounted in said housing for engagement with said cam, meansattaching said push bar with one arm of said bellcrank, a nibblercomprising a die block and a cutter reciprocably mounted relative tosaid die block, one end of said cutter bearing against one arm of saidbellcrank for reciprocation thereby as said shaft is rotated, springmeans for urging .said push bar'against said cam, and means located onsaid housing adjacent said die block to define the distance between thedie block and said housing to adjust said device for the reception lofsheets of material of different thicknesses. I

3. In a nibbler attachment for attachment to a power machine having arotatable spindle, a housing, a rotatable shaft supported in saidhousing for attachment to the spindle ofthe power machine and having acam formed thereon, a bellcrank pivoted in said housing, a push barreciprocably mounted in said housingk for engage ment with said cam,means attaching said push bar with one arm of said bellcrank, a nibblercomprising a die block and a cutter reciprocably mounted relative tosaid die block, one end of said cutter bearing against one arm of saidbellcrank for reciprocation thereby as said shaft is rotated, springmeans for urging said push bar against said cam, and means for adjustingthe die blockV relative tothe cutter to take up for relative Wearbetween the cutter and the die block.

BENJAMIN F. sqHMrDT.

